Joint for concrete pavements



W. L. ASHMORE.

JOINT FOR CONCRETE PAVEMENTS.

APPLICATION FILED OCT. 16. [920.

1,380,341. PatentedJune-Z 1921.

STATES PATENT FFICE;

WALTER L. ASHMOBE, OF MACON, GEORGIA.

JOINT FOR CONCRETE PAVEMENTS.

Specification of Letters Patent.

Patented June 7, 1921.

Application filed October 16, 1920. Serial No. 417,282.

' useful Improvements in Joints for Concrete Pavements; and I do herebydeclare the following to be a full, clear, and exact descriptlon of theinvention, such as will enable others skilled in the art to whichitappertains to make and use the same.

This invention relates to joints used in-th construction of concreteroads and pavements.

The primary object of the invention is, to provide a compressible jointto be embedded at intervals in the paving material as it is laid andbefore hardening so as to divide the pavement or roadway into blocks orsections adapted to permit contraction and expansion and preventbuckling in the finished and hardened pavement or road.

The invention will first be hereinafter more particularly described withreference to the accompanying drawings, which form a part of thisspecification, and then pointed out in the claims at the end of thedescription.

In said drawings,

Figure 1 represents a vertical sectional elevation of a portion of astreet pavement with a broken away portion of a joint or separatingdevice embodying my invention embedded therein; the compressible blocksbeing shown partly in their initial position and partly depressed asthey appear in the finished pavement; e

Fig. 2 is a vertical section taken at right angles to the section shownin Fig. 1, on the line 2-2 of 1, looking inthe direction of the arrow;and

Fig. 3 is a perspective view of a compressible block of'wedge-like ortapered form.

Referring to the drawings, in which the same reference letters areusedto denotecorresponding parts in different views, the letter Adenotes a su porting plate, preferably of sheet metal an of such lengthas may be desired to divide the pavingl material 'into blocks -.orsections of suita e len th and width, usually about four or five eet,and which is provided with a series of elongated slots at therein, nearthe up er edge thereof,

which extend vertically w en the plate is ar'ranged'in a vertical plane.A series of compressible blocks B are shdably mounted on the plate A soas to permit them to be pressed down into the plastic concrete in whichthe device is embedded. The blocks are preferably arranged in pairs, oneupon each side of the plate, diametrically opposite an adjoining block,each pair being arranged in close proximity to an adjoining pairthroughout the length of the plate. Each pair of blocks is securedtogether and supported on the base plate by means of a pin or rivet bwhich passes through one of theslots a so as to permit vertical or.downward movement the full length of the slot.

The blocks are preferably made of wood treated with creosote or otherpreservative substance and are set so that the grain of the wood isperpendicular to the road bed or line of the pavement.

In use the metal strips are arranged at sultable distances apart, withtheir lower edges resting on the sub base or foundation on which theconcrete is laid, the blocks being raised above the surface of thepaving material in which the device is embedded until the sliding pinsor rivets reach the upper ends of the slots. The plates extendupwardlyto a point near the surface 'of the finished pavement but slightly belowthe tops of the compressible blocks, when the latter are presseddownwardly into the plastic mass, and while the concrete is yet plastiethe blocks are driven down until the tops thereof are substantiallyflush with the surface of the pavement, thuscompressin the plasticconcrete below the blocks and orming a solid foundationon which theblocks may rest, the surface of the finished pavement being even withthe tops of the blocks. In this position there is left a small creviceor open space between the upper ends of the bloc s and above the upperedge of the supporting plate, and this crevice is filled with asphalt orhot bitumen or other plastic substance so that when finished the surfaceof the road or pavement will be smooth and even. a

In the construction of concrete pavements, it is a common practice toinsert at intervals pieces or strips of paper which are impregnated orcoated with bituminous material, in order to separate the pavement intoseparate blocks or sections, such separations wet, or as it is usuallycalled, green conv crete, while changing from a wet plastic condition toa hard solid state, loses in size by shrinking, and it not designedlyseparated will tear apart at irregular distances. Such thin materialserves to separate the pavement into suitable sections or blocks, butthe shrinkage caused by drying or hardening does not provide enoughspace for expansion due to heat or other causes after the pavement hashardened, and to provide for expansion as well as shrinkage a thickerjoint of elastic or compressible material is desirable. This isparticularly true of long continuous lengths of pavement like roadways,which are liable to buckle, or possibly one -slab or section will breakand mount up over an adjacent section. Thin metal sheets have also beenused, to effect a separation, such sheets being usually withdrawn beforethe pavement hardens, and thecrevice thus formed filled with hotbitumen,

which is elastic but wears unevenly with the pavement. Iron and. steeljoints wear less and therefore soon protrude above the gen eral surface,causing a; hammer blow on each abutting side, and rapidly wears thesofter material, while an elastic joint hammers down and the pavementedges spall and soon a hammer blow channels the joint out, thusnecessitating repairs. The disadvantage common to all oints formed in wthe construction of pavements under existing methods resides in the factthat they do not offer equal resistance to wear the same as thepavement.

My improved joint provides for separa tion or" the hardening pavement,expansion .of the hardened pavement and a uniform wearing surface. It isseated in and anchored to the pavement and is adjustable to its freshlyfinished surface. It will not wash out, pull out, or drive or hammerbelow the surface of abutting edges of the pavement.

The size and shape of the supporting plates and blocksvmav be variedtosuit the desires of the manu acturer or'user, or to meet difierentrequirements in practical use The blocks are preferably square andtapered, as shown in Fig. 3, so as to provide a broad base and toincrease their resistance against upward movement; the tapered formserving to eilectually anchor thehlocks and prevent them from beingdrawn out after they have been pressed down into the plastic mass and ithas become hardened, but I preferably provide each block or each pair ofblocks with an anchoring device, such as a hook C depending from andintegral with or secured to a pin or rivet in sorted through the blockor pair of blocks near the upper end thereof, so that the hook may befirmly embedded in the plastic con crete and prevent upward movement ofthe block. The supporting plates may be com struetecl of any suitab ematerial possessing upon opposite sides or" the supporting plate.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent is:

1. A joint for roadways and street pavements comprising a thin,comparatively long and wide supporting member adapted to be set on oneedge upon a sub base, and a series of comparatively small compressibleblocks mounted on and extending above'the upper edge of said supportingmember, said blocks being slidable vertically to adapt them to be raisedand depressed when arranged in a. vertical plane.

2. A joint for roadways and street pavements comprising a thin,comparatively long and Wide lower member adapted to be set on one edge,and a compound upper member consisting of a series of compressibleblocks secured together in pairs, side by side, on opposite sides ofsaid lower memher; said blocks projecting above the up per edge of saidlower member when arranged in a vertical plane, and adapted to be moveddownwardly so as to compress the plastic material on which they rest.

3. A joint for roadways and street pavements comprising a comparativelylong and thin plate adapted to be set on edge upon a sub 'base, and aseries of compressible blocks mounted on the upper edge of said plateand movable upwardly and downwiardly thereon when arranged in a verticalp ane.

4 A joint for roadways and street pave ments comprising a sheet metalplate adap ed to be set on edge upon a sub base, said plate having aseries or oblong slots therein near its upper edge which extendtransversely of its length, and a series of compressible blocks slidablymounted on the upper edge of said plate and secured thereto by pinspassing through said slots.

5. A ointfor roadways and street pavements comprising a fiat metal plateadapted to be set on edge upon a sub base and having a $611650]? oblongslots therein near its upper edge which extend transversely of itslength, and a series of compressible blocks mounted on and projectingabove the upper edge of said plate; said blocks being arranged in pairswhich are joined together dependent adjustment of said pairstransversely of said plate.

6. A joint for roadways and street pavements comprising a rigid plate ofcomparatively thin material adapted to be set on edge, and having oblongslots therein near its upper edge and a series of compressible bloc-ksmounted on said plate and arranged in pairs, each pair having a pinpassed therethrough and through one of said slots.

7. A joint of the character described comprising an oblong sheet metalplate having a series of oblong slots therein near one edge extendingtransversely of its length and a double series of blocks of woodarranged on opposite sides of said plate, each block on one side'of saidplate being secured to a block on the other side thereof by a pinuniting the two blocks and passed through one of said slots so as topermit vertical adjustment of the blocks when arranged in a verticalplane.

8. A device of the character described comprising a comparatively thinplate of a width slightly lessthan the depth of a body of concrete inwhich the plate is set on edge said late having a series of blocks ofcompresslble material mounted thereon and adjustable vertically whenarranged in a vertical plane, said blocks having means thereing a seriesof joints therein, said joints consisting of comparatively thin platesset on edge upon a sub base, and a series of compressible blocks mountedon and projecting above the upper edges of said plates, the upper endsof said blocks being substantially flush with the surface of theconcrete.

10. A joint for a concrete roadway or pavement consisting of acomparatively thin plate adaptedto be set on edge upon a sub base andembedded in the concrete, and a series of compressible blocks mounted onthe upper edge of said plate and projecting above the same, said blockshaving depending hooks thereon for anchoring them the concrete. y

In testimony whereof I aflix my signature in the presence of twowitnesses.

WALTER L. ASHMORE.

Witnesses:

L. D. MooRE, RoY W. Moore.

